Publications Details
Flow-Dimension Analysis of Hydraulic Tests to Characterize Water-Conducting Features
Most analytical solutions and computer codes for well-test analysis assume a radial flow geometry around a well even though actual flow geometries can be quite different particularly in fractured media. Accurate estimation of hydraulic parameters requires knowledge of the flow geometry. Flow dimensions, representing the combined effects of flow geometry and variations in hydraulic properties, em be interpreted from the late-time slope of the pressure derivative on a log-log plot. However, the interpreted flow dimensions could be caused by an infinite number of flow geometry and hydraulic property combinations. Identifying the correct flow geometry so that appropriate hydraulic properties can be calculated is a difficult process, requiring additional information from a variety of sources. Defining a "conservative" model for a system with nonradial flow dimensions is problematic at best. Errors are compounded when hydraulic properties interpreted by force-fitting radial model to tests in nonradial systems are used in flow and transport models that also fail to take proper account of flow geometry. Whatever the flow dimension of a system might be, proper test interpretation and careful model construction, calibration, and testing are required to provide accurate modeling of flow and transport in that system.